Production of aldehyde sulfoxylates.



UNITED STATES PATENT onrrcn.

' BAZLEN, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNOR TO BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A CORPORA- TION.

rno'nnc'rxon OF'ALDEHYDE sU Fox'yLATEs.

Application filed January a1, 1906. Serial No. 298,867.

793,610 is described the production of salts of formaldehyde sulfoxylic acid by the reduction of the known aldehyde sulfur oxid compounds, namely formaldehyde bisulfite compound, or formaldehyde hydrosulfite compound. The reducing agent which proved most useful was .zinc dust in the presence of acetic acid, although iron, or aluminium, powder, in the presence of acetic acid, or chlorid of tin, could be used. All attempts I to reduce, with zinc dust alone, the fixed alkali salts of the said aldehydesulfur oxid compounds and alsothe e uivalent mixtures of formaldehyde with the ixed alkali sulfites,

bisulfites and hydrosulfites have nothitherto been practically successful as onl small yields of the sulfoxylate were obtained. '1 have discovered that these fixed alkali salts of aldehyde sulfur oxid compounds can be reduced by means of zinc dust without the I necessity for the presence of acid, if, during the reduction, zinc sulfite, or zinc bisulfite, or a zinc salt of formaldehyde sulfurous acid, orof formaldehyde hydrosulfurous acid, be added. The reason for this appears to be that zinc formaldehyde bisulfite is directly reducible to zinc formaldehyde sulfoxylate by meansof zinc dust in the absence of extraneous acid. Thus if zinc 'sulfite or zinc bisulfite or a zinc salt of formaldehyde hydro- The zinc ramldehyae bisulfite which is either thus formed or Which has been directly addedto the fixed alkali salt of the aldehyde sulfur oxid derivative as the case may be, is then reduced by means of zinc dust yielding 1 zinc formaldeh dc sulfoxylate which then under oes double decomposition with sodium formaldehyde bisulfite forming sodium folmaldehyde sulfoxylate and zinc formaldehyde bisulfite. This latter is then reduced with an additional uantity of zinc dust, and in this way the ad ition of quite a small quantit ofzinc salt enables large quantities of sodium formaldehyde bisulfite to be reduced. When zinc sulfite or zinc bisulfite is added, it is advantageous also to add more formaldehyde so that all the sulfur introduced can be converted into formaldehyde sulfoxylate. This formaldehyde can react with zinc sulfite to form zinc formaldehyde bisulfite which is directly reducible or it can react with the sodium sulfite to form sodium forn'ialdehyde bisulfite which then undergoes the reaction above described. If, instead of zinc sulfite, or zincbisulfite, a zinc salt of formaldehyde sulfurous acid or of formaldehyde hydrosulfurous acid be employed, it is unnecessary to add any additionalformaldehyde, since there is already a sufficient quantity to com bine with the whole of the sulfur present when forming sulfoxylate.

Since zinc formaldehyde 'hydrosulfite behaves, as is known, as if it were composed of equimolecular proportions of zinc formaldehyde bisulfite and zinc formaldehyde sulfoxylate, it can be seen that for the purposes of i this'inventionzinc sulfite, zinc bisulfite and a zinc salt of formaldehyde sulfurous acid or offormaldehyde hydrosulfurousacid are equivalents, all of them giving the desired result, namely, the presence of zinc formaldehyde bisulfite which can be reduced to zinc f0rmal dehyde sulfoxylateby means of zinc alone Patented April 21', 1908.

without the presence of any extraneous acid.

Of course the addition of previpusly prepared zinc formaldehyde sulfoxylate would enable the reduction of thefixed alkali formaldehyde bisulfite to be effected in the manner "above described, but I preferto make use of one of the other above mentioned zinc salts, so that the isolation of zinc formaldehyde sulfoxylate is th'en unnecessary. I

The above description represents my View of the course of the reaction, but I do not wish to be understood as confining my invention to the exact course described or to-the i equations hereinafter given, since other chemists may hold different views upon the subect. a

The reaction should be carried out while the mixture is hot, even while it is boilin Any difiicultly soluble, or insoluble, zinc sa t be converted into soluble sulfoxylate by the addition of alkali sulfite either before,. or after, the reaction hastaken place, or, after the reaction has taken place, any other alkali salt which is convenient for precipitating the zinc, or an alkali hydrate, can be added.-

'I have discovered that instead of the above named zinc salts, the corresponding 1 ammonium salts can be employed w1th simila! results, so that they are equivalent for. this process. The typical reaction when usin ammonium sulfite being represented by the Following equation:

2(CH O.NaHSO (nng so zpcn onso nng N ,so,,

and the ammonium formaldehyde bisu'lfite compound resembles the corresponding zinc compound in being capable of reduction by zinc alone without treatment with an extraneous acid. After the formation of the} formaldehyde sulfoxylate has taken lace, a

. part ofthe ammonia combines with t e com-i pound formed.

Although I have described my invention takingformaldehyde as a typical aldehyde,

'yetI do not wish to be understood as limit- (30) parts of formaldehyde (used in the form containing a precipitate.

of a thirt while the remainder is in the (30) per cent. solution) add one hundred and eighty (180) parts of zinc sulfite, one hundred (100) parts of thirty (30) per cent. formaldehyde, two hundred (200) parts of zinc dust, and from fifteen hundred (1500) to two thousand (2000) arts of water, and, while stirring, heat the w ole at a temperature of from ninety (90) to one hundred (100) degreescentigrade, until a test portion shows that the reducing power of the mixture is not increasing. During the reaction the water which evaporates off should be replaced.

The product obtained-consists of a solution Part of theformaldehyde sulfoxylic acid formed is contained in the solution in the form of the sodium salt, recipitate in the form of a dilficultly solu le zinc salt.

This can be converted into the sodium salt by boiling with, for instance, sodium sulfite. The reactions which occur in the foregoing ssasea,

example may be represented by the following equations: of formaldehyde sulfoxylic acid obtained can Example 2: 'Heatlto ether, for some time in the manner described in the foregoin example, two hundred and fifty-two 252) parts of sodium sulfite, one hundred and eighty (180) parts of zinc sulfite, one hundred (100) parts of thirty (30) per cent. formaldeh de solution, one hundred (100) parts 0 zinc dust and from fifteen hundred- (a) NaSO, cno 11,0

NaI-ISO .CH O NaOH Example '3: Boil together for some time, I

three hundred (300) parts of sodium formaldehyde hydrosulfite, one hundred and eighty (180) parts of zinc sulfite, two hundred (200) parts of zinc dust and from fifteen hundred (1500) to two thousand (2000) parts of water. The difiicultly soluble zinc salt of formaldehyde sulfoxylic acid which is formed, and which is contained in the preci itate, can be converted into the sodium sa t by adding sodium sulfite and boiling for some time.

The reactions which proceed in the foregoing example can according to the present viewbe represented by the following equations:

Example 4: Boil together for some time,

three hundred (300) parts of sodium formaldehyde hydrosulfite, one hundred and eighty (180) parts of'zinc sulfite, two hundred and fifty-two (252) parts of sodiumsulfite, two

hundred (200) parts of zinc dust and two thousand (2000) arts of water. The filtrate contains the so Ium salt formaldehyde sulfoxylic acid which can be obtainedby evaporation.

Thelreactions according to the foregoing example are analogous to those taking place in Example 3, the addition of the sodium sulfite in this example resulting in the formation of the sodium salt of formaldehyde sulfoxylic acid at once.

. Example 5: Mix together four hundred and twenty (420) parts of forty-two (42) per cent. sodium bisullite solution, three hundred and sixty five (365} parts of neutral ammonium sulfite solution (containing one hundred and seventy (17 0) parts of (NHMSQ three hundred parts of thirty (30) per cent. formaldehyde solution and from fifteen hundred (1500) to two thousand (2000) parts of water; then add three hundred and fifty (350) parts of zinc dust, which has previously been made into a paste with a little water, and heat the mixture, while well stirring, at a temperature of about one hundred (100) degrees centigrade for one hour and a half (1.5). Filter off the zinc mud and precipitate the small amount of zinc which remains in solution and work up the filtrate, which may he done in the usual manner. In this way amixture of the sodium salt and the ammonium salt of formaldehyde sulfoxylic acid is obtained.

The reactions which occur in the foregoing example are identical with those illustrated at the end of Exam le 1 with the exception that ammonium su fite takes the place of zinc sulfite.

In the foregoing examples, instead of being boiled, the inixtures may be heated, while stirring, at a tem erature of from ninety (90) to one hundre (100) degrees centigradc,

' until test portions show that the reducing foxylate by reactin power of the mixturevis not increasing. If

the reaction be carried out at a lower temperature, a correspondingly-longer period is required for its completion.

N ow what I claim is:

1. The process of producing aldehyde sulwith a reducing metal on a fixed alkali salt of an aldehyde sulfur oxid compound in the presence of zinc sulfite while totally avoiding the presence of extraneous acid.

2.' The process of producing aldehyde sulfoxylate by reacting with zinc on a'fixed alkali salt of an aldehyde sulfur oxid compound in the presence of zinc sulfitc while totally avoiding the presence of extraneous acid.

3. The process of producing formaldehyde sulfoxylate by reacting with zinc on a fixed alkali salt of a formaldehyde sulfu'r oxid compound in the while totally avoiding the presence of extraneous acid.

1. The process of producing formaldehyde sulfoxylate by reacting with zinc on formal-' my hand in the presence of two subscribing witnesses.

MAX BAZLEN. Witnesses:

J. ALEC. LLOYD, l Jos. H. LEUTE.

resence of zinc sulfite. 

